efi: Make for_each_efi_memory_desc_in_map() cope with running on Xen

While commit 55f1ea15216 ("efi: Fix for_each_efi_memory_desc_in_map()
for empty memmaps") made an attempt to deal with empty memory maps, it
didn't address the case where the map field never gets set, as is
apparently the case when running under Xen.

Reported-by: <[email protected]>
Tested-by: <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: <[email protected]> # v4.7+
Signed-off-by: Jan Beulich <[email protected]>
[ Guard the loop with a NULL check instead of pointer underflow ]
Signed-off-by: Matt Fleming <[email protected]>

0 files changed, 0 insertions, 0 deletions